Information signal processing unit

ABSTRACT

A new additional information generating section generates new additional information FS 1  based upon information from an additional information reading section. The spectrum of the new additional information FS 1  is spread by an SS additional information generating section and supplied to a signal superimposing section as SS additional information SF 1 . The signal superimposing section generates a digital video signal S 2  by superimposing the SS additional information SF 1  on a digital video signal S 1 . A writing section records the digital video signal S 2  on which the SS additional information SF 1  is superimposed on a recording medium. Hereby, adding additional information to an information signal without deteriorating the quality of the read information signal so that the falsification and deletion are disabled, detecting the additional information added to the information signal if necessary and utilizing it are enabled.

This is a division of prior application Serial No. 09/097,732 filed Jun.16, 1998.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an information signal processing unitfor detecting additional information from an information signal to whichthe additional information is added and processing it.

2. Description of the Related Art

Recently, a reproducing unit for a digital video tape recorder (VTR) anda digital video disc (DVD) and software reproducible using these unitsare provided in numbers, digitized video signal and aural signal canalso be reproduced readily at home, and an image and a sound/voicerespectively excellent in the quality of an image and a sound/voice canbe reproduced.

Digitized video signal and aural signal or a program are plentifullyprovided via a recording medium such as the Internet and a compact discread only memory (CD-ROM) and digitized software provided via theInternet, CD-ROM and others is widely utilized using a personal computerand others.

However, in the meantime, there is a problem that software plentifullyprovided as described above and composed of digitized video signals andothers may be unlimitedly copied. Therefore, if digitized information,for example a video signal is dealt with, direct copy preventing controlsuch as copy prohibition is executed by adding a copy preventing code toa digital video signal as digital data and recording it on a recordingmedium.

Not only a copy preventing code for prohibiting or allowing copy isadded but a code for limiting the generation of copy is added to adigital video signal and more flexible control over copy is alsoexecuted.

FIG. 1 is a basic block diagram showing a copy system in case digitizedinformation is dealt and the copy system is provided with functions forsending digital information read by a digital information reading device110 to a digital information recording device 120, copying informationwhich can be copied, prohibiting the copy of information the copy ofwhich is not allowed and updating the following digital information incase a code for limiting the generation of copy exists in digitalinformation.

Copy control information as additional information is recorded inaddition to digital main information in a recording medium 111 installedin the digital information reading device 110. The copy controlinformation is provided with the prohibition or allowance of copy, thelimitation of a generation and others as control contents.

The reading section 112 of the digital information reading device 110generates a digital read information signal D2 composed of digital maininformation and copy control information added to the digital maininformation based upon a signal D1 obtained by reading information inthe recording medium 111 and sends the above signal to the digitalinformation recording device 120.

The additional information reading section 121 of the digitalinformation recording device 120 detects copy control information CCfrom the received digital read information signal D2 and sends thedetected copy control information CC and the digital read informationsignal D2 to an additional information changing section 122.

The additional information changing section 122 generates new additionalinformation based upon copy control information CC in case copy controlinformation added to a digital information signal D2 is required to bechanged and changes copy control information added to the digitalinformation signal D2 by adding the new additional information to thedigital information signal D2.

For example, if copy control information CC is generation limitedinformation of which the copy of only a first generation is allowed, theadditional information changing section 122 changes copy controlinformation by generating new copy control information the controlcontents of which represent the prohibition of copy and adding this newcopy control information to the digital information signal D2.

As a result, as described above, a digital information signal D3 towhich copy control information changed if necessary is added and copycontrol information CC are output from the additional informationchanging section 122 and sent to a writing section 123.

The writing section 123 converts the above digital read informationsignal D3 to digital information suitable for recording if copy controlinformation CC supplied via the additional information changing section122 represents the allowance of recording a digital read informationsignal from the digital information reading device 110 and writes theabove converted digital information to a recording medium 124. In themeantime, if copy control information cc from the additional informationreading section 121 represents the prohibition of copy, the wiringsection 123 does not record the above digital read information signalD3.

Further, if copy control information CC from the additional informationreading section 121 represents that the copy of only a first generationis allowed, the digital read information signal D3 to which new copycontrol information is added by the additional information changingsection 122 as described above is converted to digital informationsuitable for recording and is written to the recording medium 124. Inthis case, a digital information signal cannot be copied using a copiedrecording medium 124.

As described above, in the case of so-called digital connection that amain information signal and copy control information as additionalinformation are supplied to the recording device as a digital signal,the recording device can securely execute copy preventing control suchas the prohibition of copy using copy control information because copycontrol information is included in transmitted digital data.

As described above, even if information recorded in a recording mediumin which a digital video signal as a main information signal and copycontrol information as additional information are recorded is read usinga digital reading device and copy control information is obtainedtogether with a digital video signal, only a digital video signal whichis a main information signal can be converted to an analog signal via aD/A converting circuit to monitor an image for example and can be outputto an analog output terminal to which a picture tube of a monitor isnormally connected.

As described above, even if digital information is read by a readingdevice, a copy control signal is not included in an analog signal outputto the analog output terminal. Therefore, in the case of analogconnection in which analog VTR and others are connected to an analogoutput terminal, control over copy based upon copy control informationis disabled, for example the copy of a main information signal the copyof which is prohibited is enabled and the limitation of a generation ofcopy is also disabled.

As copy control information is often added in a header and othersseparately from a digital video signal as a main information signal evenin the case of digital connection, copy control based upon copy controlinformation is disabled and illegal copy is enabled by deletinginformation in a part to which copy control information is added andfalsifying copy control information such as replacing with anotherinformation.

Further, it is also conceivable that when copy control information issuperimposed or added in a frequency band different from the frequencyband of these video signal and aural signal even if a video signal andan aural signal respectively as a main information signal are an analogsignal or a digital signal, copy control information is deleted by asimple frequency filter and copy control based upon copy controlinformation is disabled.

Therefore, as described above referring to FIG. 1, as the signalstrength of additional information such as copy control informationadded to a main information signal is weak and additional informationcannot be regenerated in case it is once deleted even if more flexiblecopy control is executed by providing a function for changing copycontrol information as additional information to the recording device,changing additional information added to an information signal inrecording an information signal if necessary and utilizing the changedadditional information, a case that additional information added to aninformation signal cannot be sufficiently utilized occurs.

SUMMARY OF THE INVENTION

The present invention is made in view of the above problems and theobject is to enable adding additional information to an informationsignal without deteriorating the quality of a read information signal sothat falsification and deletion are disabled also in a device used by ageneral user, detecting additional information added to an informationsignal if necessary and utilizing the additional information.

An information signal processing unit according to the present inventionis characterized in that it is provided with reading means for receivingan information signal on which an additional information signal thespectrum of which is spread is superimposed and reading the aboveadditional information signal from the above information signal,additional information signal generating means for generating a newadditional information signal based upon the additional informationsignal read by the reading means, spreading means for spreading thespectrum of the new additional information signal generated by theadditional information signal generating means and superposing means forsuperposing the new additional information signal the spectrum of whichis spread by the spreading means on the above information signal andoutputting it.

According to the above unit, the spectrum of a new additionalinformation signal is spread, is superimposed on a digital informationsignal as a wide-band and low-level signal and if the digitalinformation signal is a video signal, the superimposed additionalinformation signal never deteriorates a reproduced image.

Further, as the new additional information signal is superimposed on thedigital information signal at the same time and in the same frequencyband, it is difficult to falsify or delete additional information by afrequency filter or the simple replacement of information signals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an example of a conventional typecopying device;

FIG. 2 is a block diagram for explaining an embodiment of an informationsignal recording device according to the present invention;

FIG. 3 is a block diagram for explaining a timing generating section inthe recording device shown in FIG. 2;

FIG. 4 is a block diagram for explaining an SS additional informationgenerating section in the recording device shown in FIG. 2;

FIG. 5 is a block diagram for explaining an example of a PN codegenerating section in a part of the SS additional information generatingsection shown in FIG. 4;

FIGS. 6A-D show relationship between SS additional information (copycontrol information) and an information signal in the shape of aspectrum;

FIG. 7 is a block diagram for explaining an embodiment of an informationsignal recording system according to the present invention;

FIG. 8 is a block diagram for explaining another example of the SSadditional information generating section;

FIG. 9 is a block diagram for explaining further another example of theSS additional information generating section;

FIG. 10 is a block diagram for explaining the other example of the SSadditional information generating section;

FIG. 11 is a block diagram showing an example of an SS additionalinformation detecting section; and

FIG. 12 is a block diagram showing another example of the SS additionalinformation detecting section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, embodiments of the present invention will bedescribed below.

First Embodiment

FIG. 2 is a block diagram for explaining an information signal recordingdevice 10 equivalent to a first embodiment (hereinafter called only arecording device). The recording device 10 equivalent to the firstembodiment receives a digital information signal provided via a networksuch as the Internet and records it on a recording medium. That is, therecording device 10 is obtained by applying the present invention to adevice such as a personal computer which can send and receive aninformation signal via a network such as the Internet.

Recording Device 10

As shown in FIG. 2, the recording device 10 equivalent to the firstembodiment is provided with an additional information reading section11, a new additional information generating section 12, a timinggenerating section 13, a spread spectrum (SS) additional informationgenerating section 14, a signal superimposing section 15 and a writingsection 16.

A recording medium 100 is a disc such as CD-ROM and DVD to which variousdigital information signals such as a digital video signal, a digitalaural signal and a program are written by the recording device 10.Hereinafter, to simplify description, a digital information signalsupplied to the recording device 10 and recorded on the recording medium100 shall be a digital video signal.

Additional information is added to a digital video signal S1 supplied tothe recording device 10 in the first embodiment. The additionalinformation is 1- or 2-bit copy control information representing thecontents of copy control over a digital video signal S1 such as theallowance or prohibition of copy and the limitation of a generation.

In the first embodiment, for example, a digital video signal S1 sent viaa network such as the Internet and received by the recording device 10is supplied to the additional information reading section 11 of therecording device 10 and the timing generating section 13.

The additional information reading section 11 reads additionalinformation FS which is copy control information added to a digitalvideo signal S1 from the digital video signal S1, supplies it to the newadditional information generating section 12 and supplies the digitalvideo signal S1 to the signal superimposing section 15 as it is.

The new additional information generating section 12 generates newadditional information FS1 (hereinafter called new additionalinformation) to be added to the digital video signal S1 based upon theadditional information FS from the additional information readingsection 11.

In the first embodiment, for example, when additional information FSfrom the additional information reading section 11 represents theallowance of the copy of only a first generation, the new additionalinformation generating section 12 generates new additional informationFS1 representing the prohibition of copy. When additional information FSfrom the additional information reading section 11 represents theprohibition or the allowance of copy, the new additional informationgenerating section 12 supplies the additional information FSrepresenting the prohibition or the allowance of copy to the SSadditional information generating section 14 as new additionalinformation FS1 as it is.

When additional information FS is not read from the digital video signalS1 by the additional information reading section 11 such as additionalinformation is not added to the digital video signal S1, the newadditional information generating section 12 detects the above,generates additional information FS1 based upon the number of therecording device 10 such as the serial number of the recording device 10or ID number of a user of the recording device 10 and supplies it to theSS additional information generating section 14. In the recording device10 equivalent to the first embodiment, these number of the recordingdevice 10 and ID number of a user are recorded beforehand in a memorywith which the new additional information generating section 12 isprovided.

As described above, the new additional information generating section 12generates new additional information FS1 based upon information obtainedas a result of processing for reading additional information by theadditional information reading section 11 and supplies it to the SSadditional information generating section 14.

In the meantime, the timing generating section 13 receives the digitalvideo signal S1, detects a reference timing signal from the digitalvideo signal S1 and generates a timing signal TM and a clock signal CLKrespectively used in each section of the recording device 10 equivalentto the first embodiment based upon the detected reference timing signal.

FIG. 3 is a block diagram for explaining the timing generating section13 of the recording device 10 equivalent to the first embodiment. Asshown in FIG. 3, the timing generating section 13 is provided with areference timing detecting section 131, a phase-locked loop (PLL)circuit 132 and a timing signal generating section 133.

The reference timing detecting section 131 extracts a synchronizingsignal DK as a reference timing signal from the digital video signal S1supplied to the reference timing detecting section and supplies it tothe PLL circuit 132 and the timing signal generating section 133.

The PLL circuit 132 generates a clock signal CLK synchronized with thedigital video signal S1 based upon a synchronizing signal DK from thereference timing detecting section 131. The clock signal CLK is suppliedto the timing signal generating section 133 and each section using theclock signal CLK such as the SS additional information generatingsection 14 described later.

The timing signal generating section 133 generates and outputs a timingsignal TM used by the SS additional information generating section 14described later and the other various timing signals based upon asynchronizing signal DK from the reference timing detecting section 131and a clock signal CLK from the PLL circuit 131.

In the first embodiment, a timing signal TM generated by the timingsignal generating section 133 is used for a reset (initializing) signalsynchronized with a synchronizing signal DS from the reference timingdetecting section 131 and showing timing for generating a new additionalinformation string the spectrum of which is spread and a pseudorandomnoise (PN) code string provided with a predetermined code pattern usedfor spreading a spectrum from the head in the SS additional informationgenerating section 14 described later.

For example, if it is set that the reference timing detecting section131 of the timing generating section 13 extracts a verticalsynchronizing signal as a reference timing signal, a clock signal CLKsynchronized with a vertical synchronizing signal from the referencetiming detecting section 131 is generated by the PLL circuit 132.

The timing signal generating section 133 generates a timing signal TMset so that one vertical interval (one field) is equivalent to one cycleand synchronized with a vertical synchronizing signal used for areference timing signal based upon a vertical synchronizing signal fromthe reference timing detecting section 131 and a clock signal CLK fromthe PLL circuit 132.

A timing signal TM and a clock signal CLK respectively generated by thetiming generating section 13 as described above are supplied to the SSadditional information generating section 14 as shown in FIG. 2.

The SS additional information generating section 14 receives newadditional information FS1, a timing signal TM and a clock signal CLKand generates spread spectrum additional information SF1 which is aspread spectrum signal of the new additional information FS1.

FIG. 4 is a block diagram for explaining the SS additional informationgenerating section 14 in the first embodiment. As shown in FIG. 4, theSS additional information generating section 14 is provided with a PNcode generating section 141 and a multiplying section 142.

The PN code generating section 141 generates a PN code string PS basedupon a timing signal TM and a clock signal CLK. That is, in the firstembodiment, the PN code generating section 141 generates a PN codestring PS from the head in synchronization with a clock signal CLK everytime a timing signal TM is supplied and supplies it to the multiplyingsection 142.

A new additional information string FS1R composed of each bit of newadditional information FS1 from the new additional informationgenerating section 12 output by the predetermined number of clocks insynchronization with a clock signal CLK at timing shown by a timingsignal TM is supplied to the multiplying section 142.

The multiplying section 142 generates a spread spectrum signal (SSadditional information) SF1 which is new additional information thespectrum of which is spread by multiplying the PN code string PS and thenew additional information string FS1R.

As described above, the SS additional information generating section 14is provided with a function as spreading means for converting newadditional information FS1 with a narrow band and at a high level to SSadditional information SF1 with a wide band and at a low level as alsodescribed later by spreading the spectrum of additional information FS1using the PN code string PS.

FIG. 5 shows an example of the constitution of the PN code generatingsection 141 shown in FIG. 4. The PN code generating section 141 in thisexample is composed of 12 D flip-flop circuits REG1 to REG15constituting 12 shift registers and exclusive OR circuits WX-OR1 toEX-OR3 for operating the suitable tap output of the shift register. ThePN code generating section 141 shown in FIG. 4 generates an M series ofPN code string PS based upon a timing signal TM and a clock signal CLKas described above.

An enabling signal EN in FIG. 5 is a signal for operating the PN codegenerating section 141 and in the first embodiment, the above enablingsignal is generated when the recording device 10 shown in FIG. 2 forexample is powered on and is supplied to the PN code generating section141.

SS additional information SF1 obtained from the SS additionalinformation generating section 14 as described above is supplied to thesignal superimposing section 15.

The signal superimposing section 15 receives a digital video signal S1and digital SS additional information SF1 and generates a digital videosignal S2 on which the digital SS additional information SF1 issuperimposed.

The signal superimposing section 15 superposes SS additional informationSF1 on the least significant bit (LSB) of a 10-bit digital video signaland a ninth bit which is a bit next to the least significant bit in casethe digital video signal S1 is composed of ten bits which represent animage equivalent to one picture element for example. As described above,the signal superimposing section 15 superposes SS additional informationSF1 on the digital video signal S1 at the same time and in the samefrequency band.

In this case, the signal superimposing section 15 prevents SS additionalinformation SF1 from deteriorating the digital video signal S1 bysuperimposing SS additional information SF1 on the digital video signalS1 by signal power lower than the dynamic range of the digital videosignal S1. A digital video signal S2 generated by superimposing SSadditional information SF1 on the digital video signal S1 by the signalsuperimposing section 15 as described above is supplied to the writingsection 16.

The writing section 16 receives the digital video signal S2 on which thedigital SS additional information SF1 is superimposed, converts it to adigital video signal for recording suitable for recording and writes thedigital video signal for recording to the recording medium 100. Hereby,the digital video signal on which the SS additional information SF1which is new additional information the spectrum of which is spread issuperimposed is recorded in the recording medium 100 in addition to theadditional information FS added before.

As described below, as the spectrum of new additional information FS1superimposed on the digital video signal recorded on the recordingmedium 100 is spread, an image reproduced by the digital video signal isnever deteriorated and falsification and deletion are disabled.

Therefore, if a digital video signal recorded on the recording medium100 is read or a digital video signal read from the recording medium 100is recorded (copied) on another recording medium, new additionalinformation superimposed on a digital video signal can be securelyobtained and utilized such as new additional information the spectrum ofwhich is spread and superimposed on the digital video signal isextracted and copy control is executed according to the new additionalinformation.

FIGS. 6 show relationship between additional information which isinformation such as copy control information and an information signal,a video signal in this example in the shape of a spectrum. The quantityof information included in additional information is small, additionalinformation is a signal the bit rate of which is slow and as shown inFIG. 6A, is a narrow-band signal. When the spectrum of the signal isspread, the signal becomes a wide-band signal as shown in FIG. 6B. Atthis time, the level of a spread spectrum signal is lowered in inverseproportion to the extension of the band.

The spread spectrum signal, that is, the SS additional information SF1is superimposed on an information signal by the signal superimposingsection 15, however, in this case, as shown in FIG. 6C, the SSadditional information SF1 is superimposed at a lower level than thedynamic range of a video signal as an information signal. Thedeterioration of an information signal can be mostly prevented bysuperimposing as described above. Therefore, if a video signal on whichSS additional information SF1 is superimposed is supplied to a picturetube of a monitor and an image is reproduced, the image is hardlyinfluenced by the SS additional information SF1 and a satisfactoryreproduced image can be obtained.

However, as described later, when the spectrum of SS additionalinformation SF1 is reduced to detect the SS additional information SF1in a recording device, the SS additional information SF1 is restoredagain as a narrow-band signal (additional information) as shown in FIG.6D. The power of copy control information after the spectrum is reducedis higher than the power of an information signal by applying asufficient spread spectrum factor and the copy control information canbe detected.

In this case, as SS additional information SF1 is superimposed on avideo signal at the same time and in the same frequency band, thedeletion and modification of the SS additional information are disabledby a frequency filter and the simple replacement of information.

As described above, if a digital video signal is read from the recordingmedium 100 or a read digital video signal is recorded on anotherrecording medium, new additional information the spectrum of which isspread and superimposed is extracted and copy preventing controlaccording to the extracted additional information can be executed.

If new additional information the spectrum of which is spread andsuperimposed is extracted from a digital video signal, new additionalinformation is generated in synchronization with the same PN code stringas a PN code string for spreading a spectrum and new additionalinformation the spectrum of which is spread and superimposed on thedigital video signal can be extracted by reducing the spectrum using thePN code string.

As described above, the recording device 10 equivalent to the firstembodiment generates new additional information based upon informationobtained by reading additional information added to a digital videosignal in case the supplied digital video signal is recorded on arecording medium. A digital video signal on which new additionalinformation the spectrum of which is spread is superimposed obtained byspreading the spectrum of the above new additional information andsuperimposing the new additional information on the digital video signalcan be recorded on a recording medium.

As described above, as the spectrum of new additional informationsuperimposed on a digital video signal is spread and the new additionalinformation is superimposed as a wide-band signal at a low level, avideo signal read by the digital video signal is never deteriorated.

As new additional information the spectrum of which is spread issuperimposed on a digital video signal at the same time and in the samefrequency band, the new additional information cannot be falsified ordeleted by a frequency filter or the replacement of an informationsignal.

As described above, as new additional information the spectrum of whichis spread is superimposed on a digital video signal at the same time andin the same frequency band, additional information is never deleted evenif the digital video signal on which the additional information thespectrum of which is spread is superimposed is converted from a digitalsignal to an analog signal.

Therefore, when a digital video signal on which new additionalinformation the spectrum of which is spread is superimposed is read orcopied, additional information superimposed on the digital video signalis extracted, copy control according to the additional information isexecuted, the contents of the additional information are updated and newadditional information is generated, the new additional information isadded again and more flexible control such as the limitation of ageneration is enabled. As described above, new additional informationsuperimposed on a digital video signal can be securely obtained andutilized.

As described above, for new additional information FS1 generated by thenew additional information generating section 12, new additionalinformation FS1 may be also generated by changing additional informationFS from the additional information reading section, additionalinformation FS may be also used for new additional information FS1 as itis, different new additional information FS1 from additional informationFS may be also generated or a part of additional information FS ischanged and it may be also used for new additional information FS1.

Additional information FS and new additional information FS1 may alsorepresent the same contents and may also represent separate contents. Asdescribed above, if additional information and new additionalinformation represent separate contents, the quantity of additionalinformation which can be added to a digital video signal which is aninformation signal to be recorded on a recording medium can beincreased.

Additional information FS read by the additional information readingsection 11 is supplied to the writing section 16 and copy controlaccording to the additional information SF may be also executed by thewriting section 16.

If the processing such as coding of a digital video signal to berecorded is required, the processing may be executed by the writingsection 16.

Second Embodiment

FIG. 7 is a block diagram for explaining an information signal copysystem equivalent to a second embodiment. The information signal copysystem equivalent to the second embodiment is constituted by aninformation signal reading device 20 connected via a network such as theInternet (hereinafter called only a reading device) and an informationsignal recording device 30 (hereinafter called only a recording device)as in the above first embodiment. These reading device 20 and recordingdevice 30 are applied to a device such as a personal computer which cansend or receive an information signal via a network such as theInternet.

Reading Device 20

As shown in FIG. 7, the reading device 20 is provided with a readingsection 21 and provided with a function as an information signal sendingdevice for reading and sending an information signal recorded on arecording medium 200. In the second embodiment, the recording medium 200is a disc information on which can be read by the reading device 20 suchas CD-ROM and DVD.

In the second embodiment, a digital video signal is recorded on therecording medium 200. A digital video signal recorded on the recordingmedium 200 is recorded by the recording device 10 in the firstembodiment for example.

Therefore, first additional information the spectrum of which is spreadis superimposed on a digital video signal at the same time and in thesame frequency band and recorded on the recording medium 200 and secondadditional information is added in another recording area on a track onwhich video data is to be recorded. That is, two types of additionalinformation different in an adding method is superimposed and addedon/to a digital video signal recorded on the recording medium 200.

The reading section 21 of the reading device 20 generates a digital readvideo signal S12 based upon a signal S11 obtained by reading informationon the recording medium 200 and sends it to the recording device 30 viaa network such as the Internet.

In this case, as described above, the spectrum of the first additionalinformation is spread to be a wide-band signal at a low level and thefirst additional information is superimposed on a digital video signalat the same time and in the same frequency band.

Therefore, the first additional information never deteriorates an imagereproduced based upon the digital video signal and is never falsified ordeleted. Even if a digital video signal on which additional information1 the spectrum of which is spread is superimposed is converted to ananalog signal, the first additional information is never deleted.

Therefore, the first additional information the spectrum of which isspread and superimposed on a digital video signal is securely providedto the recording device 30 together with the digital video signal.

Recording Device 30

The recording device 30 in the second embodiment is provided with afunction as an information signal receiving device for receiving andprocessing an information signal provided via a network such as theInternet. The recording device 30 in the second embodiment is providedwith an SS additional information reading section 31, a new additionalinformation generating section 32, a timing generating section 33, an SSadditional information generating section 34, a signal superimposingsection 35, a writing section 36 and an additional informationreading/changing section 37 as in FIG. 7.

Each section except the SS additional information reading section 31 andthe additional information reading/changing section 37 is the same asthe corresponding each section of the recording device 10 in the abovefirst embodiment.

A digital read video signal S12 from the reading device 20 is suppliedto the SS additional information reading section 31 and the timinggenerating section 33 respectively of the recording device 30.

The timing generating section 33 is provided with the same constitutionas that of the timing generating section 13 in the first embodimentdescribed referring to FIG. 3 and generates a timing signal Tm and aclock signal CLK used in each section of the recording device 30.Therefore, the timing generating section 33 will be explained assumingthat it is provided with the constitution shown in FIG. 3.

A reference timing detecting section 131 of the timing generatingsection 33 extracts a synchronizing signal DK as a reference timingsignal from a digital video signal S12 from the reading device 20. Thesynchronizing signal DK is supplied to a PLL circuit 132 and a timingsignal generating section 133.

The PLL circuit 132 generates a clock signal CLK synchronized with adigital video signal S12 based upon a synchronizing signal DK from thereference timing detecting section 131 and supplies it to the timingsignal generating section 133, the SS additional information readingsection 31, the SS additional information generating section 34 andothers.

The timing signal generating section 133 generates and outputs a timingsignal TM and other various timing signals used by the SS additionalinformation reading section 31, the SS additional information generatingsection 34 and others based upon a synchronizing signal DK from thereference timing detecting section 131 and a clock signal CLK from thePLL circuit 132.

In the second embodiment, these timing signal TM and clock signal CLKprovide the same timing as a timing signal TM and a clock signal CLKused by the recording device 10 equivalent to the first embodiment.

As described above, a timing signal TM and a clock signal CLK generatedby the timing generating section 33 are supplied to the SS additionalinformation reading section 31 and the SS additional informationgenerating section 34 as shown in FIG. 7.

The SS additional information reading section 31 reduces the spectrum ofa digital read video signal S12, extracts first additional informationF1 spectrum of which is spread and superimposed on the digital readvideo signal S12, supplies it to the new additional informationgenerating section 32 and supplies the digital read video signal S12 tothe additional information reading/changing section 37 as it is.

That is, the SS additional information reading section 31 is providedwith a PN code generator and a multiplying section respectively notshown and provided with functions for generating a PN code string forreducing a spectrum with the same code pattern as that of a PN codestring used for spreading the spectrum of first additional informationthe spectrum of which is spread and superimposed on a digital videosignal S12 at the same timing based upon a timing signal TM and a clocksignal CLK from the timing generating section 33 and for extracting thefirst additional information F1 by reducing the spectrum using this PNcode string for reducing a spectrum.

The new additional information generating section 32 generates first newadditional information F12 added to a digital video signal to berecorded on a recording medium 300 (hereinafter called first newadditional information) based upon additional information F1 from theadditional information reading section 31 and supplies it to the SSadditional information generating section 34 and the additionalinformation reading/changing section 37.

When additional information F1 supplied to the new additionalinformation generating section 32 allows the copy of only a firstgeneration, the new additional information generating section 32generate and outputs first new additional information F12 representingthe prohibition of copy as the new additional information generatingsection 12 in the first embodiment. When additional information F1represents the prohibition or the allowance of copy, the additionalinformation F1 representing the prohibition or the allowance of copy isoutput as it is as first new additional information F12.

When additional information F1 is not read from a digital video signalS12 by the SS additional information reading section 31 such as in caseSS additional information is not added to the digital video signal S12,the new additional information generating section 32 detects it,generates and outputs the serial number of the recording device 30, IDnumber of a user of the recording device 10 for example and others asfirst new additional information F12. New additional information forgenerating these is recorded in a memory with which the new additionalinformation generating section 32 is provided beforehand.

As described above, the new additional information generating section 32generates first new additional information F12 based upon informationobtained as a result of reading additional information by the SSadditional information reading section 31 and supplies it to the SSadditional information generating section 34 and the additionalinformation reading/changing section 37.

The additional information reading/changing section 37 extracts secondadditional information added to video data from a digital video signalS12. The additional information reading/changing section 37 generatessecond new additional information based upon the extracted secondadditional information and first new additional information F12 from thenew additional information generating section 32 (hereinafter calledsecond new additional information) and adds it to the digital videosignal S12 again.

In this case, the second new additional information is added to videodata constituted by digital video signals S12. Hereby, in the secondembodiment, second additional information added to a digital videosignal S12 is rewritten to second new additional information. A digitalvide signal S13 generated by adding the second new additionalinformation by the additional information reading/changing section 37 issupplied to the signal superimposing section 35.

In the meantime, the SS additional information generating section 34 isconstituted as the SS additional information generating section 14 inthe first embodiment, receives new additional information F12, a timingsignal TM and a clock signal CLK and generates SS additional informationSF12 which is a signal obtained by spreading the spectrum of newadditional information F12. Therefore, the SS additional informationgenerating section 34 in the second embodiment is provided with the sameconstitution as that shown in FIG. 4.

As shown in FIG. 4, the SS additional information generating section 34is provided with a PN code generating section 141 and a multiplyingsection 142.

The PN code generating section 141 of the SS additional informationgenerating section 34 is provided with the constitution describedreferring to FIG. 5 and generates a PN code string PS based upon atiming signal TM and a clock signal CLK. That is, the PN code generatingsection 141 generates a PN code string PS from the head every time atiming signal TM is supplied in synchronization with a clock signal CLKand supplies it to the multiplying section 142.

A new additional information string F12R generated by outputting eachbit of first new additional information F12 from the new additionalinformation generating section 32 by the predetermined number of clocksevery time a timing signal TM is output in synchronization with a clocksignal CLK is supplied to the multiplying section 142.

The multiplying section 142 generates a spread spectrum signal (SSadditional information) SF12 which is first new additional informationthe spectrum of which is spread by multiplying a PN code string PS and afirst new additional information string F12R and supplies it to thesignal superimposing section 35.

The signal superimposing section 35 receives a digital video signal S13to which second new additional information is added and digital SSadditional information SF12 and generates a digital video signal S14 onwhich the digital SS additional information SF12 is superimposed.

The signal superimposing section 35 superposes SS additional informationSF12 on a digital video signal S13 at the same time and in the samefrequency band as the signal superimposing section 15 in the firstembodiment. In this case, the SS additional information SF12 issuperimposed on the digital video signal S1 by signal power lower thanthe dynamic range of the digital video signal S1.

As described above, a digital video signal S14 generated by the signalsuperimposing section 35 by superimposing the SS additional informationSF12 on the digital video signal S13 is supplied to the writing section36.

The writing section 36 receives the digital video signal S14, convertsit to a digital video signal for recording suitable for recording andwrites the digital video signal for recording to the recording medium300. Hereby, the digital video signal to which the second new additionalinformation is added and on which the first new additional informationthe spectrum of which is spread is superimposed is recorded on therecording medium 300.

In the second embodiment, it is described that the first new additionalinformation superimposed on the digital video signal as SS additionalinformation SF12 is generated based upon the first additionalinformation the spectrum of which is spread and superimposed on thedigital video signal S12, however, the present invention is not limitedto this.

For example, first new additional information may be also generatedbased upon information obtained by reading first additional informationby the SS additional information reading section 31 and informationobtained by reading second additional information by the additionalinformation reading/changing section 37 and first new additionalinformation may be also generated based upon only information obtainedby reading second additional information by the additional informationreading/changing section 37.

It is described above that the second new additional information isgenerated based upon the first new additional information F12 and thesecond additional information, however, the present invention is notlimited to this. For example, the above second new additionalinformation may be also generated based upon information obtained byreading the first additional information by the SS additionalinformation reading section 31 and may be also generated based uponinformation obtained by reading second additional information by theadditional information reading/changing section 37.

As described above, second new additional information may be alsogenerated based upon first new additional information generated basedupon information obtained by reading first additional information by theSS additional information reading section 31 and information obtained byreading second additional information by the additional informationreading/changing section 37 and information obtained by reading thesecond additional information by the additional informationreading/changing section 37.

First and second additional information may be also superimposed andadded on/to a digital video signal as first and second new additionalinformation as they are without generating first and second newadditional information.

Another information different from the first and second additionalinformation is generated, may be also added as additional information, apart of original first and second additional information is changed andmay be also superimposed or added on/to a digital video signal.

If the spectrum of first new additional information is spread and thespread spectrum first new additional information is superimposed on adigital video signal using a PN code string different from a PN codestring used for spreading the spectrum of additional information thespectrum of which is spread and added to a digital read video signal S12the SS additional information generating section 34, for example PN codestrings different in a phase even if the PN code strings belong to thesame series and PN code strings different in a series, the spreadspectrum first new additional information can be superimposed on aninformation signal without being mistaken for the already superimposedspread spectrum first additional information and if necessary, can beextracted.

In the second embodiment, it is described that the spectrum of first newadditional information is spread and the spread spectrum first newadditional information is superimposed on a digital video signal,however, the present invention is not limited to this, SS additionalinformation for negating spread spectrum first additional informationsuperimposed on a digital video signal is generated and after the spreadspectrum first additional information already superimposed is deleted bysubtracting the above first additional information from the digitalvideo signal, the spectrum of first new additional information may bealso spread and superimposed.

As described above, in the case of an information signal recordingcontrol system in the second embodiment, the recording of a digitalvideo signal can be controlled based upon first additional informationthe spectrum of which is spread and superimposed on the digital videosignal and information obtained by detecting second additionalinformation added to video data composed of digital video signals andnew additional information can be superimposed and added on/to a digitalvideo signal to be recorded on a recording medium 400.

Other examples of SS Additional Information Generating Section

In the above embodiments, as described referring to FIG. 4, the SSadditional information generating sections 14 and 34 spread the spectrumof additional information composed of small bits such as one and twobits by one PN code and generate SS additional information SF1 and SF12,however, as described below, the spectrum of additional information isnot spread but a PN code itself or a mixture of a PN code and anothercode may be also superimposed on a digital video signal as additionalinformation representing the contents of copy control.

In the above description, additional information FS is equivalent to newadditional information FS1 and F12 generated by the above new additionalinformation generating sections 12 and 32 and SS additional informationSF is equivalent to spread spectrum signals (SS additional information)SF1 and SF12 the spectrum of which is spread by the SS additionalinformation generating sections 14 and 34.

FIG. 8 shows an embodiment of the SS additional information generatingsection using PN codes different in a phase.

In the embodiment, a PN code PS output from a PN code generating section1001 is supplied to a selecting section 1003 and is supplied to a shiftregister 1002. PN codes PSa, PSb, - - - , PSn obtained by sequentiallyshifting a PN code PS according to a clock signal and respectivelydifferent in a phase are output from the shift register 1002 and arerespectively supplied to the selecting section 1003.

Additional information FS as a selection control signal is supplied tothe selecting section 1003. The selecting section 1003 selects a PN codeof one phase according to the contents of control represented inadditional information FS which is a selection control signal, that is,the prohibition or the allowance of copy out of PN codes PS, PSa,PSb, - - - , PSn of plural phases and outputs it as SS additionalinformation SF.

FIG. 9 shows an embodiment of the SS additional information generatingsection using PN codes different in a series.

In the embodiment, plural PN code generators 1021, 1022 and 1023 forgenerating PN codes PS1, PS2 and PS3 different in a series are provided.Output from each PN code generator 1021, 1022 and 1023 is input to theselecting section 1024.

Additional information FS is supplied to the selecting section 1024 as aselection control signal. The selecting section 1024 selects a PN codeof one series according to the contents of control represented inadditional information FS which is a selection control signal, that is,the prohibition or the allowance of copy out of PN codes PS1 , PS2 andPS3 of plural series and outputs it as SS additional information SF.

FIG. 10 shows an embodiment of the main part of an SS additionalinformation generating/superimposing device in case one type of PN codeand plural orthogonal codes are used.

In the embodiment, one PN code generating section 1041 and orthogonalcode generating sections 1042, 1043 and 1044 for respectively generatingorthogonal codes mutually different are provided. A PN code PS outputfrom the PN code generating section 1041 is input to a multiplyingsection 1046. Different orthogonal codes respectively from theorthogonal code generating sections 1042, 1043 and 1044 are input to theselecting section 1045. Additional information FS is supplied to theselecting section 1045 as a selection control signal.

The selecting section 1045 outputs one orthogonal code according to thecontents of control represented in additional information FS which is aselection control signal, that is, the prohibition or the allowance ofcopy out of plural different orthogonal codes to the multiplying section1046. The multiplying section 1046 multiplies the above PN code PS andthe selected orthogonal code and outputs the result of themultiplication as SS additional information SF.

Detecting SS Additional Information Corresponding other Examples of SSAdditional Information Generating Section

If the SS additional information generating sections respectively shownin FIGS. 8 to 10 are used, the detection of spread spectrum additionalinformation is executed as follows:

FIG. 11 shows an example of an SS additional information detectingsection for detecting additional information from a video signal onwhich SS additional information for which PN codes of different phasesshown in FIG. 8 are used is superimposed.

In the SS additional information detecting section in this example, adigital read video signal (a received signal) on which SS additionalinformation is superimposed is input to a PN code detecting section1061. In the PN code detecting section 1061, the timing of a PN code isdetected and the result is input to an additional information generatingsection 1062. The additional information generating section 1062specifies the contents of copy control represented in additionalinformation based upon difference in timing between PN codes, generatesadditional information to be supplied to a recording control sectionaccording to the result of the specification and outputs it.

FIG. 12 shows an example of an SS additional information detectingsection for detecting additional information from a vide signal on whichSS additional information for which PN codes of different series shownin FIG. 9 or a mixture of one type of PN code and plural orthogonalcodes shown in FIG. 10 are used is superimposed.

In the SS additional information detecting section in this example, adigital video signal on which SS additional information is superimposed(a received signal) is input to PN code detecting sections 1081, 1082and 1083. The PN code detecting sections 1081, 1082 and 1083respectively detect a different PN code or a code obtained bymultiplying one type of PN code and a different orthogonal code. Theoutput is input to an additional information generating section 1084.The additional information generating section 1084 specifies the type ofadditional information based upon which code string is detected,generates additional information to be supplied to a recording controlsection according to the result of the specification and outputs it.

If the above SS additional information generating section and the aboveSS additional information detecting section are used, plural differentadditional information can be also simultaneously added by using PNcodes of different phases or a code obtained by combining an orthogonalcode and a PN code in spreading the spectrum of additional informationshowing the contents of copy control and to be superimposed.

In the above first and second embodiments, a PN code of M series isused, however, the present invention is not limited to this and variousspreading codes such as a code of a gold code series may be used.

In the above first and second embodiments, a timing signal and a clocksignal are generated using a synchronizing signal extracted from adigital video signal for a reference signal, however, the presentinvention is not limited to this.

Various timing used by each section of the recording devices 10 and 30in the above first and second embodiments may be also controlled by asystem controller for example without using a synchronizing signal froma digital video signal as a reference signal.

In the above first and second embodiments, if the coding of a digitalvideo signal as an information signal and the compression of a signalare required, the above coding and compression can be executed by thereading section 21 of the recording device and the writing sections 16and 36 of the recording device.

As described above, if 10-bit data is recorded in 8 bits for example incase a digital video signal is compressed, the deterioration and thedeletion of SS additional information can be prevented by superimposingthe SS additional information at the time of 10 bits before compressioneven if the compressed digital video signal is restored.

Also, if compression in which S-N ratio of a digital video signal isdeteriorated for example is done, SS additional information can be alsoinserted into higher order bits without limiting to low order bits suchas LSB.

The above examples show a case that an information signal is a digitalvideo signal, however, the present invention can be applied to an audiosignal and various information signals in a computer program and others.An information signal may be also an analog signal without limiting to adigital signal.

Additional information is not limited to copy control information andvarious information such as control information, related information,the serial number of a recording device, ID of a user, a recorded date,an authorized number and copyright information can be added andsuperimposed to/on an information signal.

In the above first and second embodiments, it is described that therecording mediums 100, 200 and 300 are a disc such as CD-ROM and DVD,however, they are not limited to CD-ROM and DVD.

For a recording medium, various recording mediums such as an opticaldisc, a magneto-optical disc, a magnetic disc and a magnetic recordingmedium such as a video tape may be used.

In the above first and second embodiments, it is described that therecording devices 10 and 30 and the reading device 20 are a personalcomputer which sends and receives data via a network and others,however, the recording device and the reading device are not limited tothis.

The present invention can be applied to various recording devices andrecording/reading devices such as a recording device and arecording/reading device for DVD, digital VTR, VTR and a cassette taperecorder.

As described above, according to the information signal recording deviceaccording to the present invention, as the frequency band of additionalinformation is spread by spreading the spectrum and the spread spectrumadditional information is superimposed on an information signal at thesame time and in the same frequency band, the falsification and thedeletion of additional information are disabled by a frequency filterand the simple replacement of an information signal. Even if aninformation signal is a digital signal and it is converted to an analogsignal, additional information can be prevented from being deleted. Asdescribed above, the survival rate of additional informationsuperimposed on an information signal can be enhanced.

As additional information the falsification and the deletion of whichare disabled and with high signal strength can be added to aninformation signal as described above, reliable devices and systems inwhich the deletion and others of additional information never occur canbe realized.

As the spectrum of additional information is spread to be a wide-bandand low-level signal, the additional information can be superimposed onan information without deteriorating the information signal.

According to the information signal recording device according to thepresent invention, as additional information of the same contents isadded in different adding methods, the reliability and strength ofadditional information added to an information signal can be enhanced.As falsification can be checked by equalizing additional informationadded to an information signal in different adding methods, a range inwhich additional information is utilized can be widened. Further,additional information different in contents can be also added to aninformation signal in different adding methods and in this case, thetotal quantity of additional information added to an information signalcan be increased.

According to the information signal recording device according to thepresent invention, plural additional information can be also readilysimultaneously superimposed on the same information signal and utilizedby using spreading codes different in a phase or plural differentspreading codes such as a spreading code and an orthogonal code.

According to the information signal recording device according to thepresent invention, as additional information the spectrum of which isspread is superimposed on an information signal at a low signal level,the additional information can be prevented from having an effect uponthe information signal such as deteriorating the information signal.

According to the information signal recording device according to thepresent invention, additional information can be promptly extracted bysynchronizing a spreading code for spreading the spectrum of additionalinformation and a spreading code for reducing the spectrum when thespectrum is reduced.

What is claimed is:
 1. An information signal processing unit,comprising: additional information signal detecting means receiving adigital information signal to which a first additional informationsignal and a second additional information signal are added fordetecting said first additional information signal from said informationsignal; first additional information signal generating means forgenerating a first new additional informational signal based upon saidfirst additional informational signal detected by said additionalinformation signal detecting means; second additional information signalgenerating means for generating a second new additional informationsignal based upon said new additional information signal; addition meansfor adding said second new additional information signal andsuperimposing said first new additional information signal to saiddigital information signal.
 2. The information signal processing unit asclaimed in claim 1, wherein said additional information detecting meansdetects said first additional information signal by reducing thespectrum of said first additional information signal added to saiddigital information signal by spreading a spectrum.
 3. The informationsignal processing unit as claimed in claim 2, further comprising:spreading means for spreading the spectrum of said first new additionalinformation signal, wherein, said addition means superimposes said firstnew additional information signal the spectrum of which is spread onsaid digital information signal.
 4. The information signal processingunit as claimed in claim 3, further comprising: recording means forrecording an output signal from said superimposing means.